In multistage rotary machines used for energy conversion for example, a fluid is used to produce rotational motion. In a gas turbine engine, for example, a gas is compressed in a compressor and mixed with a fuel source in a combustor. The combination of gas and fuel is then ignited for generating combustion gases (hot gas) that are directed to turbine stage(s) to produce rotational motion. Both the turbine stage(s) and the compressor have stationary or non-rotary components, such as vanes, for example, that cooperate with rotatable components, such as rotor blades, for example, for compressing and expanding the operational gases. Many components within the machines must be cooled by cooling air to prevent the components from overheating.
Cooling air and hot gas leakage between a hot gas path and a disc cavity in the machines reduces performance and efficiency. Cooling air leakage from the disc cavities into the hot gas path in airfoil channels can disrupt the flow of the hot gas and increase heat losses. Further, as more cooling air is leaked into the hot gas path, the higher the primary zone temperature in the combustor must be to achieve the required engine firing temperature. Additionally, hot gas leakage into the disc cavities yields higher disc and blade root temperatures and may result in reduced performance and reduced service life and/or failure of the components in the disc cavities.
In view of higher pressure ratios and higher engine firing temperatures implemented in modern machines, it is increasingly important to limit leakage between the hot gas path and the disc cavity in the machines to maximize performance and efficiency thereof.
In view of the foregoing considerations it would be desirable to provide a seal arrangement for use in a rotary machine, whereby the placement and configuration of sealing flanges in the arrangement limits leakage between the hot gas path and the disc cavity to thereby improve performance and efficiency of the rotary machine.